- The unit is a cart-based ultrasound system used to perform non-invasive diagnostic ultrasound studies. The system functions in a manner identical to all diagnostic ultrasound systems and transducers for the conventional modes: B-mode, Harmonic imaging, Spatial Compounding imaging and Power Doppler. Additionally, the system uses a new imaging mode based on shear wave elastography to map tissue stiffness. The elastography mode produces color-coded images of different tissues based on their elasticity. The color scale represents a quantitative assessment of tissue stiffness, thereby allowing elasticity of tissue to be quantified in units of kilopascals (kPa).